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  1. K

    Gyroscopic Forces?

    A normal spinning top will spin forever, at least in theory. However in reality there is friction, which will slow down the top over time. This will be the case with any contraption that you can come up with.
  2. K

    Minimum Energy Of A Beta Particle

    Homework Statement When Ne (Z=10) decays to Na (Z=11), what is the maximum kinetic energy of the emitted electron? What is the minimum energy? What is the energy of the neutrino in each case? Ignore recoil of the daughter nucleus. Homework Equations E = mc^2 The Attempt at a Solution The...
  3. K

    Rubber bouncing balls

    I think he is talking about that demonstration of momentum where you have several bouncing balls on top of each other, let them fall and then watch the top one bounce up very high. The question then is, is it possible with enough balls/starting height to have the top ball reach escape velocity...
  4. K

    Ignoring Rotation Of Earth

    What do you mean they would "resist" an ideal scenario? I'm assuming that by ideal, you mean the scenario mentioned in my assumption (no rotation, uniform density...), but I'm not sure how a force could "resist" something. So I hope you could clarify that point. Well, that's what I though too...
  5. K

    Interference of waves from two sources.

    Umm, try to draw the picture. You don't need to use Pythagoras.
  6. K

    Interference of waves from two sources.

    4.47m from point A??? :confused: How?
  7. K

    Interference of waves from two sources.

    You do not need the distance in this case, because the three points (two points sources and the location you are interested in) lie in a straight line. Since it is the difference in distance that you are interested in, for a straight line this is just the distance between them.
  8. K

    Interference of waves from two sources.

    L should be the distance between the two point sources, so L=2.
  9. K

    Interference of waves from two sources.

    Yes, that is exactly what it means. Since the distance is not a multiple of the wavelength, the crests do not line up with each other and neither do the troughs. Since it is not a multiple of wavelengths plus a half of a wavelength apart, the troughs do not line-up with the crests and so do not...
  10. K

    Linear momentum conservation - rocket

    Assuming that v2 is the intial velocity of R block and v3 is the initial velocity of the C block, that statement is true. (Note: Initial means before the R block is shot off).
  11. K

    Differentials and area

    Try to layout the tin can as a map. That is, if you cut the edges and and layed everything flat. How would it look like? Or lookup the equation for the surface area of a cylinder. No, deriative of something is how much one thing changes in respect to another.
  12. K

    Interference of waves from two sources.

    What is L? The equations look right, I just want to see if you know what the variables mean. From your attempt, I think you got it confused with a very similar equation for resonance.
  13. K

    Archimedes Principle and bouyant force

    That sounds about right. First you have the volume of pure iron (assuming the holes don't weigh anything ;) ) and then you have the actual volume. The difference should be the volume of non-iron stuff.
  14. K

    Ignoring Rotation Of Earth

    Hi all, Some time ago I watched this http://www.youtube.com/watch?v=FAFUSbIs5KA". However in it I assumed that the Earth is not rotating and I would like to know what would happen if I did not make that assumption I do believe that if the Earth is rotating, it will affect the speed of...
  15. K

    Archimedes Principle and bouyant force

    You were on the right track, but mass of the displaced water does not equal to the mass of the cavities. But the volume of the casting equals to the volume of the displaced water. Try to continue from there. I don't really understand what this question is asking exactly, so I'll leave...
  16. K

    Can anyone clarify the following points regarding calculus. Please

    I would write that as: 1. A function is defined as the unique relationship between two variables usually x and y. In other words, for each x there is only one y.
  17. K

    Help quick physics problem!

    I suggest that you try to break it up into three sections. The accelerating section, the non-accelerating section and finally the rough (de)accelerating section. First step is to find the speed that the rock gains as it is pushed in the first section. As tiny-tim pointed out, you do not know...
  18. K

    [CODE]stdvector<float> *my_vectors;[/CODE]does this create a

    It creates a pointer to a vector. You can tell by seeing where the * is.
  19. K

    Two Lenses In A Row

    Hmm, so it does not matter that the rays from the first lens go through the second lens and then form the first image?
  20. K

    Two Lenses In A Row

    Homework Statement Two lenses, one converging with focal length 20.0cm and one diverging with focal length -10.0cm, are placed 25.cm apart. An object is placed 60.0cm in front of the converging lense. Determine the position of the final image. Homework Equations \frac{1}{s_i} +...
  21. K

    Know all forces

    I guess I worded it wrong. I should have said "initial moving at a constant velocity, then a force..."
  22. K

    Know all forces

    To add to the discussion, you should always look for counter examples first. Don't underestimate them, as they are quite powerful. You don't even need to think about the theory if you have a counter example. For this question, there are many good counter examples. Just image you have a object...
  23. K

    What is fictitious force?

    Yup, that sounds about right. I think Pseudo-forces (that is how I heard them to be called most often) as accounting for the acceleration. What I mean by this is that acceleration happens when you don't have balanced forces, so to pretend that you have no acceleration when you are in the...
  24. K

    Optical phenomena that can be photographed?

    Putting a camera in front of a diffraction grating and pointing it at some light is quite fun. I remember doing that in my physics lab.
  25. K

    A running Spit

    I would say that it increases the distance, assuming that you spit first and then stop running. The reason is that the spit inside you already has the speed of your moving and when you spit you add to that speed. So by the time the spit hits the ground (which is independent of horizontal...
  26. K

    TI-83 question sorry

    Yup, the calculator sees it just like a 0. Calculators can't store numbers with inifinite digits, plus you get roundinig erros with very small numbers.
  27. K

    Need help to finish my homework

    You need to show us an attempt at a solution before we can help you. But I'll tell you that you need implicit differentiation for this.
  28. K

    (Homework) Integration

    Can you show us what you did? Integration should have gotten you the right answer.
  29. K

    Vector decomposition

    I have a small suggestion. Store the vectors in the form of the three x,y,z components, as you will have to decompose them anyways to do most of the math. Only convert them into the magnitude when needed (energy calculations, status display...) using Pythogeran Theorem. That is what I do in my...
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